Plasma processor

Abstract

A plasma processor comprising a plasma generating chamber which has a plasma outflow port, an evacuated plasma processing chamber which receives therein a member to be processed, such as a semiconductor substrate, and coaxial magnet means to form coaxial magnetic fields for transporting plasma from the plasma outflow port of the plasma generating chamber to the member to be processed, the distance between the plasma outflow port and the member to be processed being made shorter than the mean free path of gas remaining in the plasma processing chamber.

What is claimed is: 
     
       1. A plasma processor comprising a plasma generating chamber having a plasma outflow port, means for introducing a gas into said plasma generating chamber, means for ionizing said gas in said plasma generating chamber to form a plasma, a plasma processing chamber disposed in communication with said plasma outflow port and which receives therein at a predetermined location a member to be processed, means for generating coaxial magnetic fields at least between said plasma outflow port and said member located in said plasma processing chamber for confining the plasma effused from said outflow port within a volume defined by said coaxial magnetic fields and for transporting said confined plasma from said plasma outflow port to said member to be processed in said plasma processing chamber, and means for evacuating said plasma processing chamber such that the distance between said plasma outflow port and said member to be processed in said plasma processing chamber is less than the length of the mean free path of any gas remaining in said plasma processing chamber. 
     
     
       2. The plasma processor according to claim 1, wherein said plasma generating chamber and said plasma processing chamber form adjacent chambers within a single envelope. 
     
     
       3. The plasma processor according to claim 1, wherein said magnetic field generating means includes means for generating a coaxial magnetic field in said plasma processing chamber which diverges in the vicinity of said member to be processed. 
     
     
       4. The plasma processor according to claim 1, further including probe means disposed at least in part in said plasma generating chamber for increasing the electric potential of said plasma. 
     
     
       5. The plasma processor according to claim 1, wherein said plasma generating chamber and said plasma processing chamber are interconnected by a plasma outflow pipe extending from said plasma outflow port. 
     
     
       6. The plasma processor according to claim 1, wherein said means for ionizing said gas includes a pair of electrodes disposed in said plasma generating chamber and a magnetron connected to said pair of electrodes, and further including electromagnetic field generating means disposed outside said plasma generating chamber for extending the orbit lengths of electrons which are accelerated by the high frequency electric field established between said pair of electrodes. 
     
     
       7. A plasma processor comprising a plasma generating chamber having a plasma outflow port, means for introducing a gas into said plasma generating chamber, means for ionizing said gas in said plasma generating chamber to form a plasma, a plasma processing chamber disposed in communication with said plasma outflow port and which receives therein at a predetermined location a member to be processed, means for generating coaxial magnetic fields at least between said plasma outflow port and said located member in said plasma processing chamber for confining the plasma effused from said outflow port within the coaxial magnetic fields and for transporting said confined plasma from said plasma outflow port to said member to be processed in said plasma processing chamber, means for evacuating said plasma processing chamber such that the distance between said plasma outflow port and said member to be processed in said plasma processing chamber is less than the length of the mean free path of any gas remaining in said plasma processing chamber, and at least one preliminary evacuation chamber connected to said plasma processing chamber by means of a sealable opening to permit exchange of said member to be processed in said processing chamber without significantly lowering the degree of vacuum in said processing chamber. 
     
     
       8. The plasma processor according to claim 7, wherein said magnetic field generating means includes means for generating a coaxial magnetic field in said plasma processing chamber which diverges in the vicinity of said member to be processed. 
     
     
       9. The plasma processor according to claim 8, wherein said means for ionizing said gas includes a pair of electrodes disposed in said plasma generating chamber and a magnetron connected to said pair of electrodes, and further including electromagnetic field generating means disposed outside said plasma generating chamber for extending the orbit lengths of electrons which are accelerated by the high frequency electric field established between said pair of electrodes. 
     
     
       10. The plasma processor according to claim 9, further including probe means disposed at least in part in said plasma generating chamber for increasing the electric potential of said plasma. 
     
     
       11. A plasma processor comprising a plasma generating chamber having a plasma outflow port, means for introducing a gas into said plasma generating chamber, means for ionizing said gas in said plasma generating chamber to form a plasma, a plasma processing chamber disposed in communication with said plasma outflow port and which receives therein at a predetermined location a member to be processed, means for evacuating said plasma processing chamber so as to make the pressure in said plasma processing chamber lower than that of said plasma generating chamber and means for generating coaxial magnetic fields at least between said plasma outflow port and said located member in said plasma processing chamber for confining the plasma effused from said outflow port within a volume defined by said coaxial magnetic fields and for transporting said plasma from said plasma outflow port to said member to be processed. 
     
     
       12. The plasma processor according to claim 11, wherein said plasma generating chamber and said plasma processing chamber form adjacent chambers within a single envelope. 
     
     
       13. The plasma processor according to claim 11, further including probe means disposed at least in part of said plasma generating chamber for increasing the electric potential of said plasma. 
     
     
       14. The plasma processor according to claim 11, wherein said plasma generating chamber and said plasma processing chamber are interconnected by a plasma outflow pipe extending from said plasma outflow port. 
     
     
       15. The plasma processing according to claim 11, wherein said means for ionizing said gas includes a pair of electrodes disposed in said plasma generating chamber and a magnetron connected to said pair of electrodes, and further including electromagnetic field generating means disposed outside said plasma generating chamber for extending the orbit lengths of electrons which are accelerated by the high frequency electronic field established between said pair of electrodes. 
     
     
       16. In a method for transporting plasma onto a major surface of a member to be processed in a plasma processing chamber disposed in communication with a plasma generating chamber for generating said plasma, the improvement which comprises transporting said plasma through a magnetic field pipe extending from said plasma generating chamber to said member in said plasma processing chamber, while evacuating the remaining gas surrounding said magnetic field pipe in said plasma processing chamber so that the pressure in said plasma processing chamber is reduced in relation to said generating chamber so that the length of the mean free path of any gas which remains in said plasma processing chamber is more than a distance from the plasma generating chamber to said member to be processed. 
     
     
       17. The improvement of claim 16 wherein said member to be processed is a semiconductor substrate. 
     
     
       18. In a method for transporting a plasma onto a major surface of a member to be processed in a plasma processing chamber disposed in communication with a plasma generating chamber for generating a plasma, the improvement which comprises transporting said plasma through a magnetic field pipe extending from said plasma generating chamber to said member in said plasma processing chamber, while evacuating the remaining gas surrounding said magnetic field pipe in said plasma processing chamber so that the pressure in the plasma processing chamber is lower than that of the plasma generating chamber so that the length of the mean free path of any gas which remains in said plasma processing chamber is more than a distance from the plasma generating chamber to said member to be processed. 
     
     
       19. The improvement of claim 18 wherein said member to be processed is a semiconductor substrate. 
     
     
       20. A method for treating a semiconductor substrate by transporting a plasma thereto comprising the steps of: generating a plasma in a first chamber, said first chamber having a plasma outflow opening,   effusing the plasma in a predetermined direction from said plasma outflow opening into a second chamber,   disposing said semiconductor substrate across said predetermined direction in said second chamber, opposed to said plasma outflow opening and apart therefrom with the distance being less than the length of the mean free path of any gas which resides in said second chamber and transporting said effused plasma from said plasma outflow opening to said disposed semiconductor substrate through a magnetic field pipe extending in said second chamber from said plasma outflow opening to said disposed semiconductor substrate while evacuating the remaining gas surrounding said magnetic field pipe, thereby subjecting said semiconductor substrate to the effused plasma from said plasma outflow opening in said second chamber so as to treat said semiconductor substrate.   
     
     
       21. In a method for transporting a plasma onto a major surface of a member to be processed in a plasma processing chamber disposed in communication with a plasma generating chamber for generating a plasma, the improvement which comprises transporting said plasma from said plasma generating chamber to said member through a magnetic field pipe formed in said plasma processing chamber, while evacuating the remaining gas surrounding said magnetic field pipe in said plasma processing chamber so that the pressure in the plasma processing chamber is lower than that of the plasma generating chamber. 
     
     
       22. A plasma processor comprising a plasma generating chamber having a plasma outflow port, means for introducing a gas into said plasma generating chamber, means for ionizing said gas in said plasma generating chamber to form a plasma, a plasma processing chamber disposed in communication with said plasma outflow port and which receives therein at a predetermined location a member to be processed, means for generating a magnetic field pipe extending in said plasma processing chamber from said outflow port to said member located in said plasma processing chamber to confine the effused plasma flowing from said outflow port into said plasma processing chamber to a desired volume, and means for evacuating said plasma processing chamber so as to make the pressure in said plasma processing chamber lower than that of said plasma generating chamber, thereby providing a long means free path for the plasma in said plasma processing chamber. 
     
     
       23. A plasma processor comprising: a plasma generating chamber having a plasma outflow port,   means for introducing a gas into said plasma generating chamber,   means for ionizing said gas in said plasma generating chamber to form a plasma,   a plasma processing chamber disposed in communication with said plasma outflow port and which receives therein at a predetermined location a member to be processed,   means for generating a magnetic field pipe extending in said plasma processing chamber from said plasma outflow port of the plasma generating chamber to said member to be processed in said plasma processing chamber to confine in the magnetic field pipe the plasma effused from said plasma outflow port into said plasma processing chamber, and   means for at least partially evacuating said plasma processing chamber through an exhaust port in said plasma processing chamber disposed outside said magnetic field pipe to permit exhaustion of the remaining gas surrounding said magnetic field pipe is said plasma processing chamber in order to obtain a long mean free path for the plasma in said plasma processing chamber.   
     
     
       24. The plasma processor according to claim 23, further comprising means for applying an electric potential to said plasma confined in said magnetic field pipe. 
     
     
       25. The plasma processor according to claim 24, wherein said electric potential is effective to promote the chemical reaction between said plasma and said member to be processed. 
     
     
       26. The plasma processor according to claim 25, wherein said electric potential is lower than about 10 volts. 
     
     
       27. A plasma processor comprising: a plasma generating chamber for generating a plasma including means for introducing a gas to be ionized to form said plasma therefrom, said plasma generating chamber having a plasma outflow opening for effusing said plasma;   a plasma processing chamber disposed in communication with said plasma outflow opening and which receives therein at a predetermined location a member to be processed;   means for generating a magnetic field pipe extending in said plasma processing chamber from said plasma outflow opening to said member to be processed in said plasma processing chamber to thereby confine the plasma effused from said plasma outflow opening into said plasma processing chamber;   means for at least partially evacuating said plasma processing chamber through an exhaust opening disposed in said plasma processing chamber outside said magnetic field pipe to permit exhaustion of the remaining gas surrounding said magnetic field pipe in said plasma processing chamber so as to obtain a long mean free path for the plasma in said plasma processing chamber, said means for evacuating being cooperative with said means for introducing so as to make the pressure in said plasma processing chamber lower than that of said plasma generating chamber; and   means for applying an electric potential to said plasma confined in said magnetic field pipe so as to convert said confined plasma in said magnetic field pipe into ions at said member to be processed in said plasma processing chamber.